PSLE Vaidev had a total of 140 coins in his coin box.
15 of all the coins saved were one-dollar coins. There were 4 times as many one-dollar coins as fifty-cent coins. The remaining coins were ten-cent coins. What was the total value of all the coins in his coin box?
|
One-dollar |
Fifty-cent |
Ten-cent |
Total |
Comparison between the number of 3 types of coins |
1x4 4 u |
4x4 16 u |
5x4 20 u
|
Comparison between the number of one-dollar and fifty-cent coins |
4x1 |
1x1 |
|
|
Number |
4 u |
1 u |
15 u |
20 u |
Value |
1 |
0.5 |
0.1 |
|
Number x value |
4 u |
0.5 u |
1.5 u |
6 u |
Number of $1 coins is the repeated identity.
Make the number of $1 coins the same.
LCM of 1 and 4 = 4
Total number of coins = 20 u
20 u = 140
1 u = 140 ÷ 20 = 7
Total value of coins
= 4 u 0.5 u 1.5 u
= 6 u
= 6 x 7
= $42
Answer(s): $42